Arrangement for actuating an element in a microlithographic projection exposure apparatus

Active Publication Date: 2014-07-22
CARL ZEISS SMT GMBH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention provides arrangements for actuating an element in a microlithographic projection exposure apparatus which enable active positional control of the element with higher control quality. The invention involves performing an over-actuation in which a surplus of actuators is used relative to the number of degrees of freedom. This additional freedom can be used to mask out the excitation of natural vibrations of the mechanical structures and to achieve a better distribution of forces. Furthermore, a surplus of sensors can also be provided to detect specific natural frequencies and prevent the positional control from reacting to them. This results in statically governed forces and avoids undesired deformations of the optical element or mirror.

Problems solved by technology

In this case, however, the problem occurs in practice that the mirrors are not ideally rigid bodies, but rather each have specific natural frequencies of the mechanical structures (e.g. of a typical order of magnitude in the range of 2-3 kHz), wherein the corresponding natural frequency spectra for the dimensions of the mirrors and of the carrying and measuring structures, the dimensions increasing with increasing numerical apertures, are shifted further and further toward lower frequencies.
An excitation of the natural frequencies via the actuators can have the effect, however, that on account of the relatively low damping in the control loop comparatively large amplitudes are detected by the respective position sensors, as a result of which the stability of the control loop can be jeopardized and active positional control can no longer be operated stably or can be operated only with low control quality.

Method used

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  • Arrangement for actuating an element in a microlithographic projection exposure apparatus
  • Arrangement for actuating an element in a microlithographic projection exposure apparatus
  • Arrangement for actuating an element in a microlithographic projection exposure apparatus

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Embodiment Construction

[0071]FIGS. 1a-b firstly show schematic illustrations for elucidating one approach according to the invention in conjunction with a non-actively deformable mirror.

[0072]In accordance with FIG. 1a, a mirror 100 to be held in a defined position is conventionally mounted isostatically by virtue of the fact that three actuators 111, 112 and 113 having a force direction or drive direction perpendicular to the mirror 100 are used to position the mirror 100 in the three degrees of freedom z, Rx and Ry (i.e. with regard to displacement in the spatial direction z and rotation about the x- and y-axis, respectively). With exactly these three actuators 111, 112 and 113, the three degrees of freedom z, Rx and Ry are statically determinate. As likewise explained here with reference to FIGS. 3 and 4, however, these three actuators 111, 112 and 113 can excite elastic natural frequencies or natural vibration modes of the mirror 100.

[0073]As indicated in FIG. 1b, a higher number (in the example nA=4)...

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Abstract

The invention relates to arrangements for actuating an element in a microlithographic projection exposure apparatus. In accordance with one aspect, an arrangement for actuating an element in a microlithographic projection exposure apparatus comprises a first number (nR) of degrees of freedom, wherein an adjustable force can be transmitted to the optical element in each of the degrees of freedom, and a second number (nA) of actuators, which are coupled to the optical element in each case via a mechanical coupling for the purpose of transmitting force to the optical element, wherein the second number (nA) is greater than the first number (nR). In accordance with one aspect, at least one of the ac-tuators is arranged in a node of at least one natural vibration mode of the optical element.

Description

Cross-Reference to Related Applications[0001]This application claims priority under 35 U.S.C. §119(e)(1) to U.S. Provisional Application No. 61 / 756,086 filed Jan. 24, 2013. This application also benefit under 35 U.S.C. §119 to German Application No. 10 2013 201 082.6, filed Jan. 24, 2013. The contents of both of these applications are hereby incorporated by reference in its entirety.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The invention relates to arrangements for actuating an element in a microlithographic projection exposure apparatus.[0004]2. Prior Art[0005]Microlithography is used for producing microstructured components such as, for example, integrated circuits or LCDs. The microlithography process is carried out in a so-called projection exposure apparatus having an illumination device and a projection lens. The image of a mask (=reticle) illuminated via the illumination device is in this case projected via the projection lens onto a substrate (e.g. a si...

Claims

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Application Information

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IPC IPC(8): G02B7/185G03F7/20G02B7/00
CPCG03F7/7015G03F7/70266G03F7/70191G03F7/70233G02B7/185G02B7/005G03F7/709G03F7/20G03F7/70825G02B26/0825G03F7/702G02B5/0891G02B7/181G02B27/0068G03F7/70308
InventorBLEIDISTEL, SASCHASCHOENHOFF, ULRICHFISCHER, JUERGEN
OwnerCARL ZEISS SMT GMBH